1. Field of the Invention
The present invention relates to a dial module for a clock, more specifically a dial module provided with several pointers that move on and relative to a timescale on a dial and which are driven by the clock mechanism.
2. Description of the Related Art
Among the mechanical clocks or clocks with an analogue readout, two major categories can be distinguished between.
A first category, the best known, is that of the traditional clock provided with a dial and pointers in the form of hands that turn around an axis under the effect of the clock mechanism.
A second category, less known, is that of the clock equipped with rotating rings or disks provided with an inscription. The disks or rings are placed directly on the drive shafts of the clock mechanism, and they replace the pointers. On the rings are the figures that correspond to the time function of the ring, i.e. the figures 1 to 12 for an hours ring, 1 to 60 for a minutes ring and a seconds ring. A reference or frame affixed on the clock indicates the reading markers or lines, with the figures being on the outermost fixed ring.
The first category of traditional clocks with pointer and dial presents the advantage of being able to rely, in collective thought, on a practically archetypical reading reflex. Our cognitive processes are such that a quick glance is sufficient to know the time, without having to read in detail the figures at which the pointers are pointing.
A disadvantage of this category is that it mechanically implies that the time indication is structured in layers, with each pointer being in a different plane in order to avoid intersections between the pointers.
This means that the pointers cover one another in certain positions, or that other information such as information relating to the date can be covered.
Likewise when the clock is equipped with additional functions, such as a chronometer, a 24-hour indication, the phase of the moon, an indication of the operating reserve and other indications of this type, these functions are inevitably temporarily covered, entirely or partially, which impedes or even prevents their reading in such a situation.
An example of a clock with pointers and dials, that is structured in layers, is described in the document EP 0921 451.
Another disadvantage of such a structure in layers is that because of this, a parallax error occurs when reading the time, such that a different time is read according to the visual angle from which the time is read. The time read is thus only correct when the time is read from a visual direction perpendicular to the dial.
The second category, less well known, presents the advantage that the rings or disks do not cover one another, at least when they are arranged in the same plane.
However, the intrinsic disadvantages of this category are that the user, when he wants to read the time, is required to attentively read the figures in order to know what time it is. To this is added the fact that, because of the geometric structure in rings, the figures are of a limited size. The poor reading ergonomics of this category constitutes an important reason for its low market share.
An example of a clock with disks is described in the document CH 676074. A disadvantage of this clock is that the time cannot be read in a known intuitive way and that a prior explanation is required to know how to use the clock. In addition, this clock presents the aforementioned disadvantages linked to the fact that the pointers and the dials are not in the same plane.
An example of a clock with disks and rings is described in the document EP 1 003 085. In addition to the disadvantages of being difficult to read, such a clock, as described in the document EP 1 003 085, presents the disadvantage of having a relatively substantial diameter given that a free space is required between the pointers and the dials, because of the eccentric rotation of the pointers on the dials. The pointers and the dials are thus not on a continuous surface. Dirt and dust can accumulate in the aforementioned free space between the pointers and the dials, and can disturb the good operation of the clock.